In the display area of the AMOLED (Active-matrix organic light emitting diode) display device, the pixels are arranged in an array comprising multiple rows, multiple columns. Each pixel generally utilizes a pixel circuit comprising two thin film transistors and one capacitor for performing driving, i.e. the 2T1C driving. This 2T1C design is sensitive to the following factors: threshold voltage (Vth) and channel mobility of thin film transistor (TFT), starting voltage and quantum efficiency of OLED (organic light emitting diode) and transient process of power supply. These factors can result in uneven brightness when different OLEDs emit light. Therefore, it is generally necessary to use a compensating circuit to reduce the influence of these factors. For example, 7T1C circuit composed of seven thin film transistors and one capacitor and 6T2C circuit composed of six thin film transistors and two capacitors.